Process for producing crimped yarns



Patentedsept. 22, 1959 PROCESS FOR PRODUCING CRIMPED YARNS Ernst Weiss and Karl Risch, Wattwil, Switzerland, as-

signors to Heberlein Patent Corporation, New York, 'N.Y., a corporation of New York Application October 22, 1952, Serial No. 316,14

3 Claims. (151-157 This invention relates to a process for making permanent crimped yarn of synthetic polymerized organic material. r

Processes for producing crimped yarn by high twisting, setting and detwisting are known. Yarns treated by these known methods have been found to have varying physical characteristics.

The principal object of the present invention is to control the characteristics of such yarns and to produce yarns which shall possess characteristics desired for knitting and otherwise.

The invention comprises the novel products as well as the novel processes and steps of processes according to which such products are manufactured, the specific embodiments of which are described hereinafter by way of example and in accordance with which we now prefer to practice the invention.

It has been found in accordance with the present invention that crimped yarns will vary in accordancewith the amount of high twist given the yarn, but when the yarn is twisted in accordance with the equation given below, a superior crimped yarn is produced which is relatively permanent, is voluminous and has generally pleasing appearance. It also has a relatively high total percentage elongation and a low percentage; tension, the latter being referred to hereinafter as fiber elonga tion. Under total percentage elongation we understand the elongation of the yarn on applying adefined stress, this elongation being composed of the stretching out of the crimp and of the strain of the fibrous material itself. Under fiber elongation we. understand the strain of the fibrous material itself. These last-mentioned and quoted characteristics are further determined in connection with formulae which will be given below.

The above-mentioned equation is as follows:

whereby T means the optimum number of twists and D the denier number of the yarn. By means of this simple technical equation the optimum number of twists for different yarn titres can be easily obtained with the necessary accuracy, whereby the wearisome empiric determination of the number of twists is avoided. It has been found in employing this equation that it is particularly effective in establishing the proper number of twists to be given the yarn for yarns of 20 to 450 denier.

The present invention refers especially to fibers of polyamides, as for instance polyhexamethylene adipamide or the polymerisation product of epsilon-caprolactam. It, however, may be employed also with other synthetic polymerized organic textile fibers, filaments or yarns such as polyesters or polyvinyl compounds.

Yarns made in accordance with the present process are permanently crimped, have a round cross section and are voluminous. They possess a high total percentage elongation and a low fiber elongation. The total percentage elongation is obtained by use of the following equation:

gixloo u to 4.00%

where (a) is theyarn length measured at a load of .002

gram/denier, and (b) is the yarn length measured at a load of 0.8 gr./den. The fiber elongation is calculated as follows:

for the most suitable twists as a rule about 512% where b is the yarn length measured at a load of 0.1 gr./den. and b is the yarn length measured at a load of 0.8 gr./den.

The following are examples of the process as it is now desired to practice it in accordance with the invention.

(1) As a starting material a yarn made of the linear poly condensation product hexamethyleneadipamide is used, which is well known in the market under the name of nylon. It consists of 10 filaments and shows a total titre of 30 denier. According to the above equation the optimum twist for the high-twisting can be obtained as follows. V

/3 of the yarn quantity are high-twisted to 3860 T/m S, /a to 3860 T/m 2. Then it is steamed to set it for half an hour at 2.7 atmospheres. The yarn which is high twisted in the S-direction is detwisted to 150 T/m Z, the yarn which is high twisted in the Z-direction is detwisted to 150 T/m S, and finally the two yarns of 150 T/m 2, plus one yarn of 150 T/m S are twisted together to 100T/m S. In order to facilitate the mechanical workup, the twist of three-ply yarns usually are sized afterwards with an aqueous solution of polyvinyl alcohol plus glycerine. After washing out the sizing, the fiber material has an intensive, uniform crimp or curliness, the thread becomes considerably more voluminous and is very elastic. The total percentage elongation is of the order of 400% and the fiber elongation is of the order of 12%. Knitted and woven goods of this yarn show a completely new character in textiles and an outstanding heat retention capacity.

(2) Nylon yarn according to example 1 of a total +800=3860 Tlm titre of 70 den, consisting of 23 filaments, is high-twisted half of the quantity each in Z and 8 direction. The hightwisting is carried out on a ring twisting frame, and the yarn is then wound onto aluminum tubes. The hightwisted yarn is steamed on the rigid aluminum tubes for 45 minutes at 2 atmospheres. Then the yarn is detwisted to T/m S resp. to 100 T/m Z and thereafter one yarn each of S and Z direction is twisted together to 100 T/m Z, and finally reeled. After a short steaming without pressure there results an extraordinary and very uniform, crimped, voluminous twist of a soft and woollike hand of high elasticity and of an outstanding warmth retention. The crimp is washproof. The total percent- 291g; yelongatiod was 225% and the fiber elongation was (3) A polyamide yarn of type Perlon L or Grilon, made of a spun polycondensation product of epsiloncaprolactam, of a total titre of 300 den., is high-twisted to x w i}, and wound on rigid tubes in Z-direction. Then the yarn is steamed on tubes for 30 minutes at 1.2 atmospheres, detwisted to 80 T/m S, reeled and treated in hank form with, ,a,qneons steam, {or a shortv (time. A yery, intensive and equal crimp of the fiber material will be ohtained under heavy contraction. The yarn becomes very voluminous and elastic and shows an extraordinary soft and agreeable hand. The total percentage elongation is more; than 20.0% andwthe fiber elong tion; is about 151%:-

Y mS. made :in. accordance with-the above examples havens pleasing :annearanee. an their pr per ies With r spect to the total percentage elongation and;fiber .elon: gation along with their rounded across section render them highly desirable for .processinginto knit wear.

The properties in the yarns are illustrated on the attaohed drawing'ifiorrrning tpartaof thisapplication. In this drawingth'e course ofithe elongation as compared with .the load applied isshowntfor yarns of various :titres. The load in grams per denier is shown as the ordinate :y and the valuesaofrthe abscissa x show the elongationvpercent. Eoneachmf .the=yarns shown a basic load of .002 grJfden. is chosen which. corresponds with ianpelongation of 50% Curves shown yarns of fibers made of the linear polycondensationflproduct of hexamethylene adipamide (nylon), eachconsisting of double twists of yarns of various titres. made in accordance with :the above ex amples. Curved: refers to 21,30/2' S yarn (twist in 8-- direction of two single yarns of 30 den. each), curve II to a 40/2 S-yarn, curve III to a 70/2 S-yarn and curve IV to a 200/2 S-yarn.

From this drawing, as well as from the following chart which shows the-single elongation values at the various loads for each-yarn, -itis evident that the new product shows a remarkably high elongation.

, 30/2S-yarn 40/2S-yarn 70/2 S-yarn 1 20012 Syarn load, ,elong. load, elong. load, elongf, load, ,elongp gra /den grJden, griden. gn/den,

All elongationsin the above .table areexpressedin percents.

Furthermore, if'we figure out the strain of .thefibrons ma erial, in fiber elongation, which means the ,proporr tionate elongation within 0.1 and 0.8 gr./den. load, expressed in percentso'f the total length of the yarn loaded with 0.8 gr./den., we get the following values:

Percent 30/2 S-yarn 6.2 40/2 S-yarn 6.9 2.0/2: .srya zn 200/2 S-yarn 7.2

where T is: the number of turns per meter twist and D is the denier of the yarn, setting the yarn, thenvuntwisting thesame to a nolfimal twist, and plying said yarn with anothersirnilarly but oppositely twisted, set and untwisted yarng the, extent of; twisting, setting and .untwisting being such as to produce a plied yarn having a total elongation betwefin 150aand 400% and .a fiber elongation between about 5 audio-7a,

2. ,A processas set forth inrclaim 1 wherein the yarn isiso twisted, setrand nntwisted as to produce a plied yarn having a 'total elongation between 150 and 400% and a fiber elongation of 5 to 12%.

'3. ,A process asset torth inclaim, 1 wherein the yarn is a. polyamide yarn.

References Cited in the .file of this patent UNITED STATES PATENTS 2,019nss Heberlei-n Oct. 29, 1935 2,019,185 Kagi Oct. 29, 1935 2,295,593 Miles Sept. 15,1942 2,465,996 Y Bloch- Apr. 5, 1949 "2,564,245 Bil-lion Aug. 14, 1951 2,5 g5 18 Valentin Feb. 12, 1-952 FOREIGN PATENTS 660,993 Great'Britain Nov. '14, 1951 

1. A PROCESS FOR PRODUCING A VOLUMINOUS, PERMANENTLY AND UNIFORMLY CRIMPED SYNTHETIC ORGANIC TEXTILE YARN HAVING A HIGH TOTAL ELONGATION AND A LOW FIBER ELONGATION, WHICH CONSISTS OF THE STEPS OF TWISTING IN A SINGLE OPERATION A YARN OF A DENIER OF 20 TO 450 IN ACCORDANCE WITH THE FOLLOWING EQUATION: 